Non-interfering switch device.



G. LMUELLER. NONINTERFERING SWITCH DEVICE.

APPLICATION FILED N0v.1. 1912.

Patented sept.' 7, 1915.

3 SHEETS-SHEET 1.

G. E. MUELLER.

NON-INTER'FERING SWITCH DEVICE.

APPLICATION HLED N0v.1. 1912.

'Patentedsepn 7, 1915.

SHEETS-s115112.

@f5 A ff' l /57 G. E. MUELLER.

NON-[NTERFERING SWITCH DEVICE.`

APPLICATION FILED Nov. 1. 1912.

1 1 52,963. Patented Sept. 7, 1915.

3 SHEETS-SHEET 3.

Z/ Z/ 272755555. jizz/92725K' mw EEUFQIQE/Z/UE//EF in which a pluralityof actuating members are provided and means associated therewith sTATEsPATENTOFEIOE.

GEORGE-E. MUELLEE, OP LA GRANGE, ILLINOIS, ASSIGNOE To KELLOGGSWITOHBOARD AND SUPPLY COMPANY, OE CHICAGO, ILLINOIS, A` CORPORATION OPILLINOIS.

a citizen ofthe United States, residing in La Grange, county of Cook,and State of Illinois, have invented .certain lnew andA usefulImprovements in Non Interfering a specification. I

My invention relates to-.switching devices,

having to do more particularly with devices SwitchDevices, of whichtheifollowing is to. prevent interfering operations ofthe actuatingmembers. In otherwords my invention relates moreparticularly tononinterfering switching devicesin which no two or more actuatingmembers can be simultaneously and effectively operated.

Invill'ustrating my invention I havecho'sen to embody it in electricalv.keys Of switch-ing devices, but in'its broader aspect my invention isnotllimited to suchpartic'ular delvices.

Fora better understanding of my inven tion reference is to be had to theaccompany-- ing drawings i-n which-j Figure 1 i-s a side elevation ofone form Aof my. invention with the actuating mem- 1 Fig. 1; Fig. 3showsthekey of Fig. 1 with one of it-s actuating members moved to aneffectiveposition and another one of the actuating members partlydepressed but held against effective operation; Fig. -1 is a-detail1view of one, of the locking plates usedfor locking theactu'atingmembers against effective operation F-ig. 5 shows two of theactu- ,ating members of the device of Fig. 1 simultane'ously depressedbut held against effective operation; Fig. 6 is a side .view of anotherform of my invention; Fig. 7 is a vertical"section-through one of theactuating' ating members of Fig. 9.i Fig. 11 is a rear supporting plate.for holding the locking members of F 9; Fig: 12 is a'front sup-A portingplatel for said locking members; Fig. 13 shows in detailthe`non`interfering mech.-

anisiii ofthe device of Fig. 9; Fig.4 14fillustrates the manner in whichan actuated pluni Specification of Letters Patent.

`spectively.

' 'Patented Sept. a, 1915.

` .Appiicaaon md Nqvember i, 1912.- seriai No. malos.

ger prevents simultaneous actuation. of an` other plunger, of the deviceof Fig. 9; Fig.

15 is anotherform of my invention arranged to prevent asimultaneouseffective operation of adjacent actuating members; Fig. 16 i's avertical section through actuating member D of Fig. 14; Fig.17-illustrates the manner in which onel Off-the actuating members isheld against effective operation. with. an adjacent plunger depressed;and Fig. 18 is another modification' of my invention.

Referring now to the form Of my invention illustrated in Figs. 1 to 5,it -comprises a frame having a top plate 1 carrying an `escutcheon plate2, Adepending ends 3 and 4, and connecting plates 5 and 6 which areattached by means of screws 7. A block of insulating material S slottedto receive the sets Of contact springs 9,10, and an insulating strip 11is placedv between block S and strip 5, and clamping screws 12 extendthrongh the strip 5, insulating strips 8, 11, and into the plate 6. Aplurality Of actuating members.A, B,C, D, preferably. plunger rods,areprovided, comprising the central A rod 13 which passes through thealined bearings 14 and 15 vof the plate 1 and strip 8 revided for theactuating members normallycompressed and resting between the lcollar 17and block 8. A sleeve 18 preferably of some insulating material restsbetween the collar 17 and a shoulder on the central shaft 13, saidsleevelS being adapted to actuate the contacts 9, 10 when a plunger rodisfully depressed. A nut 19 is threaded on the upper end of rod toprovide a shoulder against which the button 20 engages when threaded ontothe end of shaft 413.` A common locking plate 21.is Slidinglysupported at its ends in the depending frame portions 3, 41, and has achamfered orifice 211 resting against the rod 13. A retractile spring 22is suitably fastened to the inner, Surface of end piece 3A and actingupon-locking plate 21 in such a manner that when al plunger is depressedthe cam 23 carried thereby moves the plate 21 against the tension ofspring 22 until the upper or locking surface of cam 23 has passed belowplate 21 when said spring 22 forces the plate back into lockingpositionas indicated in Fig. 3. The move-4 A retractile spring 16 isproy by. A common contact set 2l is insulatingly Y mounted upon the endpiece l and a` common 9, 10 are operated as shown in Fig. 23.

plate is provided, being slidiiigly supported Aat its ends by thedepending frame portions 3, 4, said plate having chamfered orifices 251adapted to cooperate with the corresponding cam 23, to actuate thecoinmon contact set 2l. when a plunger is depressed to its effective oroperative position as shown in Fig. 3. 1n the embodiment of my inventionnow being described the means to prevent simultaneous effectiveoperations of the plungers includes a plurality of locking plates 2Gslidingly supported by a plate 2T having upturiied edges forming'tlangesQ71, between which plate 26 is held. A cap plate 2S is attached by meansof screws 38 to the ends 3, l of the fiame so as to hold the lockingplates 2G in the supporting plate 27. Said plate 2S has guiding slotsQ81 through which the guidingpins 2.() extend. .aid pins 29 beingthreaded through the collars 17 to engage the shafts 13 and therebysecurely holding the collar upon the shaft. yfhe plates Q6 have angularcam surfaces Q61, Q62 which are adapted to be engaged by the stop pins9.9 when a corresponding plimger is depressed. llach plate 26 coperateswith two plunger stops 2t) and the plates are `movable by thecooperating stops 29 according to the positionin which the plunger isdepressed. rFlic plates 26 are also adapted to act upon each other tolock unoperated plungers as will be pointed out in the description ofoperation. To prevent excessive longitudinal movement of plates 2o, pins80, 3l are driven into the flange 272 as indicated in Fig.

Having described in detail the construction of the form of my inventionillustrated .in Fig. 1, the operation thereof will now be described.

Assuming all of the plungers are in their normal position and the secondplunger-13 from the left Iis depressed, upon the starting of thedownward movement, the plunger cam .28 carried thereby moves the commonlocking plate 21 toward the left against the tension of spring 22 andupon cam 23 reaching a position below or free of the locking plate Q2,said plate is moved back by spring 22 to its locking position asillustrated in Fig. 3. The down "ard movement of the plunger is arrestedwhen the contact springs This downward movement or actuation of 'theplunger also causes its cam Q3 to engage and move the eoinmoncontactplate toward the, left thereby operating the common contactsQL, saidcontacts being illustrated in Fig. 1 but not in Fig. 3. Also uponactuation of the plunger B stop pin 29 carried thereby engages the camsurfaces 261, 262 the cooperating locking plates Q6, 26A,

respectively.. Plate 2G is thereby moved toward the left to prevent aneffective operation of plunger A and plate 26A is moved toward the rightthereby also moving plate 2613 the last two said yplates preventing aneffective operation of plungers C and D. r1`his is illustrated in Fig.ln the embodiment of my invention as illustrated in Fig; l, 1 havearranged the actuating members with indicating positions, at whichposition they are not effective. That is, when an actuating member visdepressed to its effective position as shown by plunger l, upon theoperator releasing the pressure of the finger the plunger will restoreuntil the cani 223 rests beneath the common locking plate 21, at whichtime the contact springs l), 10 are interrupted. lilith the plunger l`in its indicating position, stop if) thereof is still in position tohold the locking plate in a locking position and shouldthe operatorattempt to actuate another plunger such as plunger C for example, and atthe same time hold B down, plunger, C can be only partly rvdepressed,that is it can be depressed until its stop Qtengages the locking plate2u* which will occur before the corresponding contacts 9, 10 areactuated as illustrated in Fig. 3. Of course due to the plate QW beingengaged byplate 2G, effective. operation of actuating member D is alsopre- 'vented and likewise plate Qt prevents effec operator attempt tosimultaneously aetuate any two or more plunger-s. the stops 2f andplates 2G will cooperate to prevent it. Assuming now that plunger B hasbeen actuated and returned to its indi ating position, thereafter whenthe operator depresses an other plunger such as plunger C for example`the camy 23 carried thereby engages and moves eommon locking plate 23 toallow restoration of the actuated plunger "i wherelby said plungerBrestores removing its stop Q9 out ofthe path of locking plate Qtr* sothat '.the continued advance of plunger C to an effective position, ispermitted. It is to be understood that contemplate applying thenon-interfering mechanism of Fig. 1 to keys having any number ofactuating members as well as to the exact device shown.-

flilso the locking plates 26 may be changed and modified to cooperatewith the actuating members in various ways and still come within thescope yof my invention.

spending t vpartsof-'the first for'm of my invention arev indicated bylike reference characters. The 'modification novv under consideration"differs from the first form of my invention in the particularnon-interfer ing'mechanism employed The actuating members A,"B, C, and Dof Fig. 6 .corresp'ond to the plungers-of'Fig. 1 in that they.,

, also have effective andfindicating positions.

Sofar as the keys ofFigs. 1 and 6 -are conlcerned the indicatingposition may, or may not be used. That is if desired, the contactsprings and insulating sleeve may be so con-.

structed. thatthe contacts Will be operated when the plunger is in theposition wherein it is held by the commonlocking plate. In the device ofFig.'6 I provide non-'interfering means. including locking plates 40,'41,

- 42 slidingly supported at 43 in the dependl ing end pieces 3,4. Thelocking plates 40, 41, 42' are provided With holding slots and camsurfaces adapted to coperate with the stops'29. 4These slots and `camsurfaces are so arranged that when `a plunger is depressed the platesare so moved or held that the other` plungers are pr'eventedfrom beingleffectively operated. In using four actuat- 42 are used. Each platehaving a slot, (as.

ing members A,B, C, D, three plates 40, 41,

401 in plate 40) oset with respect to the others lotsof thepplate sothat when the ac-v tuating'plunge'r corresponding to the offset 4slot isdepressed, the stop 29 carried by said member either moves the plate to,orho'lds it in, a position whereby its other slots are oset andthe camsurfaces (as 403plate 40)` tend to lock the remaining plungers againstleffective actuation. Plate 40 has an .offset slot 401 for plunger A,plate 41 has an offset slot 411 for plunger B, and plate 42 has anoffset slot 421 for plungerC. If five or more actuating members are'tobe provided, then I find that the number of locking plates required isone'lessthan the number of actuating members, there being a plate foreach 'l actuating member except one,` which as is indicated in Fig.v 6,is the actuating member D. The locking plates are loosely supported attheir ends in the parts 3, 4, that is they are slidingly held so as toremain in any posi- .tion to which they are moved. Assuming that plates40, .'41, 42, are in the relative position indicated in Figs. 6 and 8,actuat- -ing member D may be depressed to an effec-v tive, or toalocking position whereby the stop I29 carried thereby ivill en'terfvholding slots 402, 4,12, 422 thus holding plates-40', 41,

42 in the relative position shown so that the cam surface 403 is beneathstop '29, cam 413 is beneath stop 29 of plunger B, and cam 423 isbeneath the stop 29 of plunger C. Should any of these plungers A, B, Cbe actuated and plunger D held in itsindicating or in its effectiveposition, plunger's A, B, or C could only be depressed until theirstop29 engages a cam surface of `o'ne of the locking plates, which movementis not sufficient to `bring the plunger to an effective position.Assuming now that plunger D has been moved into a locking position andits stop'29 is thus in the slots 401, 411, 422, should the operatordesire to actuate one of the .other plunger-s, as B for example,

she4 Will depress said plunger -ivhereby its".

cam :23 Willactuate the common lockingplate 21 to'release the previouslyoperated plunger D before the stop 29 reaches the locking plates.Therefore upon stop 29 of B engagin'g the' cani 413 its 4furthermovedotted circles the position assumed by the Stops 29. with respect tothe locking plates,

y.When the plungers are in indicating and effective positionrespectively.

Figs. 9 to 14:'In the device. illustrated in` Figs. 9 to 14. inclusive,the actuating mein-- bers A, B, C, and D are preferably arranged withoutany locking mechanism. That is, when depressed by the operator, uponsaid operator releasing his hold upon the actuating member it isrestored to normal by action of restoring spring 10.' It is to beunderstood though that means for locking the lactuating member down inan indicating or in an effective position maybe provided if desired, forinstance such as disclosed in Fig. 1. A common locking plate as 21 maybe added and annular cams 23 provided on the plunger rods. 'In theembodiment now under. discussion, pivoted plates 50 to 55 inclusive, -assliou'n'in detail in Fig. 13, are provided to coperate with the plungerrod stops 29 to prevent simultaneous effective actuation of more thanone plunger rod. Thepivoted plates 50 to 55 inclusive are supportedbetween the 'plates 5G, 57 said plates 50, 57 being attached to the endpieces 3, 4, in a` 'suitable' manner.. In Fig. 13 the construction andrelative positions of the pivoted locking'plates is shown, said platesbeing pivoted' from their respective bearings 501, to 551 inclusive, thepivot points for these plates at the supporting plates 50, 57 beingindicated by like reference characters 501 to 551 inclusive. In Fig. 13the piv` oted locking plates ,are illustra d in the position they bearwith respect 'to ltne plunger i rod .stops 29. Locking plates 53, 54,have with the `tree operation ot plate 53.

upwardly extending stop engaging portions which are adapted to cooperate-with the stops 29, these locking plates beingso shaped to allowclearance for intermediate stops 25).

5 That is. taking plate :'i' Yfor example. .its

etlective position as indicated in l-fy the movement thereotl causes itsstop Qi) to engage the lel't end ot the locking plates 50. 5?), 55 totilt them to the position indicated by the dotted lines, Fig. 13. inFig. lt but .20 the single plate 50 isillustrated to show the manner inwhich an engaged plate is moved to prevent simultaneous actuation ot asecond actuating member. The actuation ot' member A fauses a closure otthe contacts t), l() and while member dit is held down the Ynin-engagedends of plates 50, 53, .35 are in a position to prevent an eti'ectiveoperation 'tot' plungers B, C and t) respectively. Again assumingallplungers at normal. should the SOVmember YB be actuatech then its stop29 tilts the locking'plates-O, 51, -t to bring their iin-engaged endsinto position to prevent ettective operations ot the other plungers. Theparticular, non-interfering mechanism of the embodiment of my inventionnow under consideration is not limited to the number ot pli-ingers oractuating members shown, but may be extended to include any number otactuating members desired. To

40 extend the non-interfering mechanism ot' Figj to a device with agreater number of plungers than that illustrated, a combination ofpivoted plates may be provided in which a connection is extended betweenea ch possible combination of two plungers.

Figs. l5 to 1T: '.lfhe key illustrated in l5 to l? diters somewhat fromthe previously described keys in that the non-inter- `tering mechanismis arranged to prevent simultaneous eti'ective actuation of adjacent vplungers only. "that is, the non-interfering mechanism will not permitsimultaneous aetuat-ion ot adjacent plunger-s as .fr and B but willpermit simultaneous actuation oi plungers which are not adjacent as andC or l and D. lfhe present device is also arranged with indicating andeii'ective positions as the devices of Sheet l. rthis will be readilyunderstood from the reference characters 50 used which correspond to thereference characters indicating like parts on sheet l.

In the present device the plunger stop 2) is' an annular rib asdistinguishing from the pin stop 29 used in the previous de it 66pivoting locking plate 60 spans each pair ot1 intese adjacent plungers.having fingers (34.-, normally resting upon the stops 25). Said lockingplate is pivotally attached to a bracket (3;) and a flat tension spring(33 is provided tor pressing the locking plate 5() inwardly so that itsstop Gl may be brought in the path of plunger stop 29 when thecorresponding plungers are simultaneously depressed. Atssuming all otthe actuating members at normal and that member is actuated, upon beingdepressed its cam 23 is moved beneath the common locking plate 2l asshown in Figs. la, 1U. The downward movement ot' plunger i) carries itsstop 25) away `from tinger (Sie but as linger 35 resting upon the stop2) ot' member E, plate n() remains stationary. To actuate the contactsit, 10. plunger l) is depressed toits ilullest extent which is itseti'ective position, whereby its insulating sleeve 1S closes contactbetween springsl 5), l0, but upon the operator removing the pressureupon plunger l) it restores toits indicating position as shown in Fig.l5. Should the Yoperator depress any ot' the other ililungers, lockingplate 2i is moved to allow the release or restoration otthe previouslyactuated member. unless it is wiltully held down. But should theoperator accidentally depress two ot the adjacent plungers D and E inoperating the device, upon moving these plungers downwardly the stops fo' members D and l move Ytree ot' fingers (Si. (35 allowing ,plate UO tomove in 'ardly and place stop pins (il, in the path ot the plunger stopsQ9 as shown in Fig. l? thereby preventing an el'ltectivf'e operation ot'said plungers D, E.

Fig. 1S: Tn lf3 'i have illustrated diagraimnat-ically anon-iiitertering switch device in which electrical circuits are involvedin the control of the non-intertering mechanism. fr i' which is adaptedwhen two or more actua tin-i1: members are siinultaneously depressed,prevent 4an et/ective operation ot' said Er pair of contacts 7l., 72 areprovided for each plunger and adapted to close 'the circuit throughcorresponding resistance 73 and the winding ot magnet Y() to battery.The resistances T3 and magnet IO are so ar ranged that when a single setot contacts "il, i2 are closed. suliicient current is not permitted toflow through the winding` of inagnet 70 tocause its operation but it twoor more sets of contacts Ti, 72 are simultaneously'closed, thensu'llicient current is permitted to flow through the connectedresistances 73 to permit an eiiiective operation olE magnet 'i'O.' ifi.pivoted arm it provided tor each plunger rod. said member 7sthaving ayielding locking stop fastened thereto and adapted to be moved into thepath ot the plunger op 29 when the armature TG ot magnet 70 is att actedAlink 77 connects armature 7o o the `Divoted mem- Liv control magnet 7()is provided' `bers 74 whereby all of said members 74 are moved by theoperation of magnet 70.

For the purpose of illustrating an application ofmy invention, -I haveshown four operatingmagnets a., 1),'0, (l, corresponding tacts 9, 10,and the common conductor 7S to ground atnormal Contact 79. Thislast'described path which includes the normal conn tact 79 of magnet 70is an alternatemeans `to prevent a simultaneous effectiveloperation ofthe magnets a, I), c, (Z. That is, when magnet 70 is energized due -to asimultaneous operation of severalactuating members, normal contact 79 isinterrupted thereby removing' ground from the common conductor 7 8 andpreventing'energizatien of the mag,- nets agb, c, d l y f 'In operatingthe device of Fig. 1S, assuming theactuating member D is depressed,

contacts 71, 72 thereof are closed thereby establishing a circuitthroughthe corresponding resistance 73 and the winding of magnet 7 0. tobattery. This circuit will noty allow sufficient current to flow throughthe winding of magnet 70 to attract its armature. Therefore a continuedmovement of plunger D is permitted and its locking cam 28 is movedbeneath the common locking pla-te 21 and corresponding contacts 9, 10are closedl thereby establishing a circuit for magnet .(Z, traced frombattery through the .winding-of said magnet (l, contacts 9, 10,

conductor v78 and normal contact Y 79 to ground. Magnet d Should anotherplunger as C be depressed, its cam 23 will'release the previouslyactuated phingerD beforeits contacts7l, 72 'are closed sozthat thepreviously actuated plunger D will restore and open its contacts 7l, 72,and 9, 10 whereby the'continued advance of member C is permitted assufficient current is not permitted to flowthrough magnet to cause itsoperation; i

Should an operator intentionally or by accident depress any two or moreactuating members A, B, C, D, a Acorresponding number of resistances 73are included in circuit of magnet 7 0 whereby suliicient current willflow through the winding of magnet 70 to cause its operation. Itsarmature is therefore attracted moving the locking stops v into .thepath of the plunger stops 29 before the contacts 9, 1Q, of the actuatedplungers are engaged. Thus it will be seen that by the actuation of thelocking stops 75 a simultaneous effective operation of the actuatingmembers is prevented mechanically. Also responsive to the operation ofmagnet 70 as just described, its normal contact 79 is interruptedthereby preventing the closure of an operating circnitfor the magnets a,b, c, or

is thus energized.

,Z.- In this way an alternate non-interfering means are "provided inaddition to the mechanical means previously described.

.limited to the arrangements shown, neither do I desire to be limited tothe application of myinvention to electrical switching keys `as thenon-interfering features may be readily applied to other devices and Iaim to cover all that which comes within the spirit and scopeof theappended claims.

What I claim as new and desire .to secure by United States LettersPatent is:

l. A switch device comprising three or more actuating-members, meanscomprising a plurality of sliding bars for preventing a simultaneouseffective operation of more than one actuating member, and means forlocking an actuated member against restoration until a second member isactuated.

2. A switch device comprising three or more'v manually operated members,control mechanism individual to each of said manual members, meanscomprising a plu- Itlwill be apparent that in the particular arl ralityof endwise movable elements for pre- .l

venting a simultaneous effective operation of 4more than one manualmember, and meansA for locking an actuated member against restorationuntil a second member is actuated.

3. A switch device comprisingthree or more manually operated members. 'acontrol y.device individual to each of said members and adapted to beoperated thereby, means comprising sliding bars controlled by saidmanual members to prevent a simultaneous effective operation of morethan one of said manual members', and means for locking an actuatedmember against restoration until a second member is actuated,

fl. A device of the -character described comprising three or moreindependently operable actuating members, control devices iiidividual tosaid members and adaptedl to be tuated member against restoration untila second member is actuated.

5. A device of the characterI described comprising three or moreindependently operable actuating members,`switch contacts lindividual tosaid members andv adapted to be operated thereby, means comprising aplurality of sliding bars forpreventing a simultaneous operation of saidswitch conments for preventng;- simultaneous actuation ot' more than onemember to their operative.

positions.

12. A switching` device comprisinga pluvialit)7 of actuating memberseach having than one olf said manual members, and means for locking anactuated member against restoration until a second member is actuated.

7. A. switch device comprising` three or more independent manuallyoperable nicmbers, switch contacts for each of said members andadapte'dto be operated thereby, means comprising a plurality of slidinpTbars eit'ective when more than one of said actuating` members aresimultaneously moved, to prevent an effective operation thereof', andmeans for locking an actuated member against restoration until a secondmember is actuated. l

A switching device comprising actuat- ,ing members havingT operating andrestoring; movements. means tor locking an actuated member againstrestoration and means comprising a plurality of bars wherebywhen apluralitv of such members receive simultaneous operating' movementeffective operation thereof is prevented.

9. A switching device' comprising-a plurality of actuating members eachhavingnormal, indicating, andA operative positions, switch contacts forsaid members actuated when a member is moved to itsoperative position.and means comprising a plurality 'of bars for preventing simultaneousactuation ci" more than one member to their operative positions'.

10. A switchingr device comprisinga pluralitv'ofv actuatingr memberseach having; normal, indicating, and operative positions,

switch contact for each of said members actuated when a member is movedto its operative position, and means comprising; endwise slidable barsfor preventing,r simultaneous actuationl of more than one member totheir operative positions.

11. A switching device comprising a pluralit;v of actuating members eachhaving normal, indicating, and operative positions, switch contacts forsaid members actuated when a member is moved to its operative position,means whereby the last member actuated is maintained in its indicatingposition, and means comprising eiidwise slidable eleiiorinal andoperative positions. switch contacts toi' said members actuated when amember is moved to its operative position, i

means ior locking' an actuated member against.restoration until a secondmember is actuated, and means includingY endwise slidable bars forpreventing` simultaneous actuation of more than one member to their saidoperative positions.

13. A switching device comprising` a plurality of actuating` memberseach havingA i normal and operative positions. restoring' means tor saidmembers tending to ell'ect their restoration when moved Yfrom normal,switch contacts for said members actuated when a member is moved to itsoperative position,mv.ms t'oilockinn an actuated member to prevent itsrestoration b v said restoring means'until a second member is actuated,and means comprising' a pluralit'v7 ot bars Ytor preventinglsimultaneous actuation of more than one member to their operativeactuation of' more than one switch contact.

15. A switching device comprisingT a pluralitlv ot actuating` memberstor controlling contact devices, means tor locking*r an actuated memberagainst restoration until the second one ot said members is operated,and means comprisingY a pluralityY ol adjacent sliding bars torpreventing the siniultaneous operation ot' more than one ot said membersto operate said contact devices.

Signed bv me at Chicago, county ot (look and State ot' illinois, in thepresence of two witnesses. Y

GEORGE E. MUELLER.

lVitnesscs M. R. Rocinfoin), Bessin OBninN.

